Use simple 2-wire cables of at least 1.5 mm2, if the speakers are relatively far apart use 2.5 mm2.

Speaker cables with a stranded wire, cable lug or banana plug connector are required (all possible on the Denon device).
These cables can be found at Digitec under "Speaker cables".
I connected my passive speakers directly to the Denon RCD-N12DAB using the stranded wire of the cable.
I also connected the device to a new Samsung TV using an "HDMI ARC" cable. This way I have the TV sound on the external speakers with much better bass tones and better stereo effect than with the internal TV speakers.

You have to use speaker cables, which can be found at Digitec under "Home cinema sound / speaker cables". https://www.digitec.ch/en.... I think these should be ok: "LogiLink CA Speaker cable, 25 m, 2.50 mm²". Maybe the thinner version with 1.50 mm² will do. Have a look at the connections. Your device has connection options for bare cables without plugs, presumably including the speakers. It's better to clamp the cable like this than to have to deal with a plug.